The invention is concerned with a sealing device for the closure of puncture holes in blood vessels.
In the case of invasive investigations and intervention in medical practice, it is necessary that access be gained to the system of blood vessels in question (arterial or venous). This can take place surgically by direct vision or by way of percutaneous puncture whereby the blood vessel must first be located xe2x80x9cblindxe2x80x9d with a hollow needle (so-called feeling with the needle). After feeling with the needle, a tracer is then inserted through the needle into the blood vessel. When the positioning of the tracer has been verified, the needle is removed over the tracer. Next, a dilator is pushed in over the tracer with the objective of making the puncture opening large enough to position a so-called xe2x80x9csheathxe2x80x9d or xe2x80x9cintroducerxe2x80x9d in the blood vessel. This sheath consists of a hollow tube made of plastic whereby one extremity, which is open, is pushed up into the blood vessel and the other extremity, which is sealed by a so-called xe2x80x9chemostatic valvexe2x80x9d, is left outside the body. The hemostatic valve is made of rubber and is designed in such a way that objects (in particular, tracers and catheters) can be inserted through it into the sheath and can then be withdrawn again through it without this leading to blood being lost out of the sheath. The dilator is removed after the sheath has been inserted into the blood vessel by passing it over the dilator. In this way, an access route to the blood vessel remains open through which tracers, catheters etc. can be inserted with ease. The sheath is removed from the blood vessel after the procedure is finished. As a result, an opening remains in the blood vessel (the so-called puncture site) through which blood can flow to the outside (bleeding). In order to stanch bleeding from the puncture site, the blood vessel must be closed by applying pressure (pressing) in order to allow time for the blood clotting mechanism to form a clot at the puncture site. Depending on whether the patient has had larger or smaller amounts of anti-clotting agents (anticoagulants), the time over which pressure has to be applied varies, in the case of an arterial puncture, from 15 minutes to more than an hour. Once the bleeding has stopped, an elastic bandage (pressure bandage) is placed over the site of the puncture; this exerts pressure so as to prevent the blood clot from being washed away by the pressure in the blood vessel which can easily happen, especially in the case of an arterial puncture. This pressure bandage must remain in place for some time, varying from clinic to clinic from 8 to 24 hours. During the period of time that the pressure bandage is in place, the patient must remain resting in bed. After removing the pressure bandage, the patient can become mobile again. After an intra-arterial examination, this usually means, in practice, that the patient must stay in the hospital overnight and then go home the following morning.
The procedure is associated with quite a few complications which are inherent in the technique which is currently used. Thus intense bleeding can occur in addition to aneurysms (outward swellings of the wall of the blood vessel at the site of the puncture) and pseudo-aneurysms (whereby a passage exists, via the puncture site, between the lumen of the blood vessel and a clot situated around the blood vessel (hematoma). Arteriovenous fistulas (passages between the arterial and venous systems of blood vessels) can also arise. Neighboring nerves can also become pinched if bleeding is sufficiently profuse, resulting in pain, sensation disturbances or even paralysis of the groups of muscles which are innervated by these nerves. These complications arise in approximately 1% of all procedures. Surgical intervention is sometimes necessary whereby the hematoma is relieved and the puncture site is sutured over (and, if required, any fistula is sealed).
In accordance with the invention, a means is envisaged to provide immediate closure of the puncture site by means of a sealing device which is introduced into the blood vessel through a sheath. This sealing device must be of such a form that it lies in the puncture site in a stable manner, does not seal the lumen of the blood vessel, does not cause intraluminal thrombi and decomposes after a certain period of time without causing emboli to form. In addition, repeated puncture of the same segment of the blood vessel must remain a possibility and there must be no allergic reactions to the material used. Of course, the material used must also be non-toxic and must be bio-compatible.
This objective is achieved in accordance with the invention by means of a sealing device for the closure of openings in blood vessels which comprises an element that is capable of unfolding, which is introduced into the blood vessel, together with a fixation attachment connected to it. In this way, the element which is capable of unfolding can even serve as a sealing element if it is constructed in the form of a flexible sheet. However, it is also possible to use a tubular element as the sealing device that is pushed into the blood vessel. In addition, it is possible to construct the sealing element in the form of an inflatable element. The fixation attachment preferably consists of a thread. In the event that a flexible sheet is used as the sealing element which is introduced into the blood stream, then, in accordance with a preferred embodiment of the invention, an arresting element is applied over the fixation attachment on the outside of the blood vessel.
The elements and/or the fixation attachment in accordance with the invention preferably consist of bio-resorbable material. An example of this is collagen. In the event that the fixation attachment comprises a fixation thread, the bio-resorbable material is, for example, the same material that is used for surgical suturing thread, e.g. catgut or polyglactin.
The sealing device is also termed an occluder in the following specification.
In an embodiment of the occluder in accordance with the invention, the sealing elementxe2x80x94also called a plugxe2x80x94is designed in such a way that it unfolds in the blood vessel after passing through the sheath and can, therefore, no longer come out again. In such an embodiment, the plug is preferably essentially circular, heart-shaped or oval. The fixation attachment or the fixation thread remains on the outside of the blood vessel in such an embodiment and is held in place by the skin. The fixation attachment is positioned through the site of the puncture. During removal of the sheath, the plug which has been inserted into the blood vessel is carefully pulled back toward the puncture site. The fixation attachment is preferably positioned essentially in the center of the flat sheet or in the vicinity thereof. The plug completely seals off the puncture site after the sheath has been removed. The fixation attachment can then be sutured to the skin.
In another embodiment, the sealing element is applied to the blood vessel from the outside and the element which is capable of unfolding is inserted into the blood vessel in order to provide a means of fastening the fixation attachment to which the sealing element is joined. In such an embodiment, it is not necessary that the element which is capable of unfolding has a flat, sheet-like form; on the contrary, it can take any form as long as satisfactory points of contact are provided on the inside of the blood vessel. In such a case, the sealing element can comprise a displaceable, tubular part which passes tightly over the fixation attachment and which is moved by the wall of the blood vessel. This type of arrangement can be effected by means of a tube or a small pipe.
The material of the plug, in particular collagen, causes a clot to form locally that is located in contact with the internal or external wall of the blood vessel; the material is completely resorbed during the course of time, usually over a period of several weeks.
Spontaneous resorption also takes place over a period of several weeks when using the preferred embodiment of the invention, i.e. a plug of collagen and a resorbable fixation attachment.